LANCE NEMATODE EFFECTS ON ROOTING OF TWO ST.AUGUSTINEGRASS CULTIVARS

摘要

St.Augustinegrass [Stenotapharum secundatum (Walt.) Kuntze] is the predominant turfgrass in Florida and other areas of the southeastern Coastal Plains of the USA.The wide spread planting of the cultivar ‘Floratam’ led to the selection of a southern chinch bug (Blissus insularis Barbar) biotype that overcame the resistance originally identified in Floratam.A new cultivar,‘Captiva’ has been released with resistance to the ‘Floratam’ resistant chinch bug biotype,but failed sod installations have raised concerns regarding its susceptibility to nematodes.The effects of lance nematodes [Hoplolaimus galeatus (Cobb) Thorne] on rooting strength of field sod installations of ‘Floratam’ and ‘Captiva’ were measured at various intervals after sod installation over two years using a sod lifting devise.Numbers of lance nematodes in the soil beneath each cultivar were determined at each sampling date.There were no differences between cultivars in the number of lance nematodes in the root zone.In 2010,root pull force for sod lifting,and root soil volume below lift grids was higher for Captiva than Floratam at most lifting dates,whereas in 2011 there were no differences between the cultivars regarding force needed to lift sod.Nematicide and fungicide treatments in 2011 also did not result in differences in sod quality after installation.Future research will focus on comparing fungal disease response between Captiva and Floratam.